The invention relates to a device for positionally-accurate accommodation of at least one secondary member on a carrier, the secondary member comprising of a seat-engaging surface.
CNC centers of rotation, for example, frequently operate with tool revolvers that have been fitted with tools, mostly preadjusted, for turning on a lathe, boring, milling, or executing other special functions. The tools are first clamped into toolholders that have been specially matched to the to the tools to be held. The interface between the tool carrier, which generally demonstrates a plurality of stations and is highly switchable from station to station, and the tool carrier arranged within the station in question is called a toolholder receptacle. The need for tool changing frequently arises in practice when manufacturing different kinds of workpieces, automatic tool-changing systems being known for this. To make the tool changing simple and avoid long set-up times, which could be required for example if it were necessary to readjust the toolholder with respect to the tool carrier, tools that have already been preadjusted should be located into the stations of the tool carrier as accurately as possible. This assumes that the toolholder receptacles of the separate stations of the toolholder (e.g. turret disc) align very exactly with the working axes of the tool receptacle. Since manufacturing tolerances in the workpiece carrier are unavoidable, there exists in practice only the option of using suitable adjusting devices to precisely align a station of the tool carrier onto the working axis of the workpiece receptacle. The toolholder receptacles in the other stations of the tool carrier each feature more or less large deviations of position depending on the tolerances of the major parts of the toolholder and their mounting.
To compensate for these deviations of position, it is known for toolholders to demonstrate additional adjusting means that permit balancing of the existing positional tolerances on the toolholder receptacles of those stations of the tool carrier that aren""t exactly aligned with the working axes. DE 199 40 330 C2 describes an example of such a toolholder system. These toolholder systems have thoroughly proven themselves in practice, although the adjusting means provided on the toolholder can only be preadjusted in such a manner that they compensate for the deviation of position of a specially allocated toolholder receptacle of the tool carrier. If the preadjusted toolholder were to be inserted into another station of the tool carrier, then the adjustment would have to be changed to compensate for the tolerances present in that station. Expensive readjustments could consequently be required for each tool change, depending on the tool changing system and type of application.
In principle, similar problem definitions also result in so-called zero voltage systems, as used for many different purposes in tools and measuring machines. This involves accommodating, positionally exact in relation to predefined working or measuring axes and in a carrier that could be in the form of a supporting table or slide, clamping devices, measuring devices, calipers, and workpiece holders or toolholders bearing stationary or rotating axes, and in being able to approximately balance existing positional inaccuracies of the carrier within prescribed tolerance limits in an easily reproducible manner. In principle, similar applications arise in attaching handling gear, such as grippers, for robots, automatic handling devices and the like.
It is thus the object of the invention to create a device of the aforementioned type that permits the manufacturing or positional tolerances of a carrier to be balanced in a simple manner, thus making it possible to fit a secondary member, perhaps in the form of a toolholder, onto a carrier, such as a tool carrier, with highly precise and reproducible positional accuracy.
To solve this object, the device according to invention features the characteristics of claim 1.
In this new location device, the locating means demonstrate a bearing surface, which is laterally arranged on the carrier in the vicinity of its seat-engaging surface. Adjusting means arrange this bearing surface on a locating member that is adjustable with respect to the carrier. The secondary member to be accommodated similarly bears stopping means, which are located in the vicinity of its seat-engaging surface, allocated to the locating member, and which, for the secondary member fastened to the seat-engaging surface of the carrier, are held up against the bearing surface with prestress.
In a preferred embodiment, the bearing surface is designed on a locating ledge of the locating means, which is adjustably attached to the carrier.
The basic idea in a location device of this sort, such as in the form of a turret disc for a tool carrier, consists of performing the precise positionally correct alignment and locating of the respective secondary member, such as a toolholder, on an adjustable bearing surface, especially on an adjustable locating ledge of the carrier. For a carrier in the form of a turret disc, the locating ledge, for example, can each time be attached in the center of the station on a annular end face of the turret disc in correspondence with its purpose. This will easily result in a perfectly adjustable stopping face, perhaps in the center of the workpiece receptacle (in the turning center of a CNC center of rotation for example). In this manner, it is ensured that the stopping faces for the toolholder will be aligned with the working axes of the workpiece receptacle on all stations of the tool carrier with great accuracy. No additional adjusting means for adjusting and balancing position errors are required on the toolholders or secondary members themselves in general. They can therefore be finished with high accuracy, the design of the bearing surface on the aforementioned locating ledge leading to very simple structural factors for the toolholder or secondary member, factors that not only ensure the high finishing accuracy desired but that also permit the toolholder to be accommodated on the carrier in manner that greatly saves space, for example. Since, in the design of the new device as a new tool clamping device, the adjustable bearing surface precisely aligns the toolholder receptacles in the individual stations of the tool carrier with the working axes of the workpiece receptacle, the toolholders can also be inserted into the toolholder receptacle of the tool carrier in any desired station that corresponds to the workpiece""s purpose without any trouble when changing tools.
Further developments of the new location device are the subject matter of the dependent claims.